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Nettie Maria Stevens
Nettie Maria Stevens (1861–1912) was an American geneticist and one of the first to discover the role of chromosomes in determining sex. She conducted research on mealworms, where she observed that male insects had one large and one small chromosome (now known as X and Y), while females had two large chromosomes (X and X). This work led to the conclusion that sex is determined by the chromosomal combination. Despite her significant contribution, she didn't receive full recognition during her lifetime, as many of her discoveries were overshadowed by male colleagues, like Edmund Beecher Wilson.
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RESULTS OF INVESTIGATIONS. Termopsis angusticollis. In the termite it was not found to be practicable to dissect out the testes. The tip of the abdomen was therefore fixed and sectioned, young males whose wings were just apparent being used. The cells are all small, and could not be studied to advantage with less than 1500 magnification (Zeiss oil immersion 2 mm., oc. 12). In the spermatogonium there...
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COLEOPTERA. Trirhabda virgata (Family Chrysomelidæ). Two species of Trirhabda were found in larval, pupal, and adult stage on Solidago sempervirens, one at Harpswell, Maine, the other at Woods Hole, Massachusetts. The adult insects of the two species differ slightly in size and color, the germ cells mainly in the number of chromosomes, Trirhabda virgata having 28 and Trirhabda canadense 30 in...
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